Apparatus for removing grit from



July 28, 1953 s. L. TOLMAN 2,647,085

APPARATUS FOR REMOVING GRIT FROM SEWAGE Filed March 28, 1949 IQAI mam; v

INVENTOE; SAMuEL. L.TC I MAN,

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HTT'X Patented July 28, 1953 APPARATUS FOR REMOVING GRIT FROM SEWAGE Samuel L. Tolman, Columbus, Ohio, assignorto The Jeffrey Manufacturing Company, a corporation of Ohio Application March 28, 1949, Serial No. 83,932

1 Claim. 1

This invention relates to apparatus for collecting .and treating solids settled from a flowing stream of liquid, such-as the grit settled in a grit channel from a stream of sewage, and an elevator mechanism associated with a grit hopper, in which there is a screw conveyer which controls the delivery or flow of the collected solids into .the bottom or boot of the elevator.

. An object of the invention is therefore to produce an apparatus of the above mentioned type.

A further object of the invention in a more detailed aspect is to provide in apparatus of the above mentioned type a trash removing screen ahead of thegrit hopper at the influent end of .the settling basin or grit channel, together with conveyer means for moving settled solids for- .wardly or in an upstream direction through the grit channel and into the grit receiving hopper; :there also being a screw conveyer in the grit re- :ceiving hopper, the operation of which is controlled by the operation of a grit removing elevator, which screw conveyer when the elevator is not operating prevents the flow of grit from the grit channel into the elevator.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claim.

In the accompanying drawing,

1 Fig. 1 is a side elevational View of an installation incorporating the features of my invention; Fig. 2 is a sectional view taken on the line 22 of Fig. 1, looking in the direction of the arrows; and

Fig. 3 is an enlarged view of a modification of the controlling cylindrical feed pipe and associated screw conveyer which controls the flow of the solids from the grit hopper into the bottom or boot of the dewatering elevator.

Referring first to Fig. 1 of the drawings, it will be seen that there is a settling basin or tank in the form of a grit channel H) which may be of poured concrete, through which solidsbearing liquid, such as sewage and the like, may flow, the liquid'entering the channel l adjacent the left-hand 0r influent end, as illustrated by the arrow, and flowing therethrough. Grit channel I0 is shown as a part of a building within which additional apparatus is housed, as hereinafter described.

As the liquid flows through the substantially unrestricted infiuent end or opening of the grit channel it is screened by a trash screen ll with which raking mechanisms I2 are associated which are carried on a pair of endless chains 13. The rake mechanisms l2 remove accumulated trash from the screen H andudischarge it into a receiving hopper M, by which it is delivered to a grinder l5, from which the reduced material is delivered to the flowing stream. The construction of the screen H and associated parts may follow that disclosed in my application, Serial No. 76,518, filed February 15, 1949, for an Improvement in Bar Screening Apparatus for Flowing Streams of Water.

Also adjacent the influent end of the grit channel or basin l0 and just downstream of the screen ll there is a grit hopper l6 which is generally trough or V-shaped in cross-section and which is formed in the bottom of said grit channel It]. The axis of the grit hopper It extends transversely of the longitudinal axis of the grit chan nel I0, or, in other Words, transverse to the normal fiow of fluid therethrough.

Adjacent one side of the grit hoppper l6 there is a receptacle in the form of a de-watering bucket elevator I1 which is separated from the grit channel I0 and the hopper I4 by a wall or partition IS. The dewatering elevator I1 is adapted to elevate sludge, grit or other solids which accumulate in the grit hopper I6 and dewater it to some extent while it is being elevated. The elevated solids are delivered to a jig, washer or other receptacle l9 wherein the inorganic solids are preferably scrubbed of adhering organic material, or, in other Words, the grit is washed, the cleaned grit being discharged along one path and the removed organic material being returned to the flowing stream.

To control the feed rate of the accumulated solids from the grit hopper IE to the boot or bottom of the receptacle or elevator H, the wall or partition I8 is provided with a cylindrical feed .pipe 20, through which the solids must pass from the hopper Hi to reach the receptacle or elevator H.

In the bottom of the grit hopper [6 there is a spiral or screw conveyer 2i having a shaft 22 mounted at one end in an appropriate bearing adjacent one side wall of the grit channel In. The shaft 22 of the screw or spiral conveyor 2| extends entirely through the feed pipe 20 and the other end is supported in an appropriate bearing in the bottom of the bucket elevator l1, said shaft 22 thereby constituting the foot shaft of said bucket elevator IT. The head shaft of the bucket elevator H is power driven from a motor 23 and thus the screw conveyer 21 is driven from said motor 23 through the chain of said bucket elevator l1.

The flights of the screw conveyer 2| at its discharge end have their peripheries adjacent the inner cylindrical wall of the feed pipe 20, said flights preferably being radially continuous from the shaft 22 and preferably being so correlated vator.

to the length of the feed pipe that at least two full flights thereon extend into said feed pipe 20.

As a consequence of this construction it is evident that the solids which accumulate in the grit hopper 16 will flow into the receptacle or bottom of the elevator i1 only as controlled by the rotation and feeding action of the screw conveyer 2|.

The speed of the Spiral or screw conveyer, the diameter of the foot sprocket of the elevator H, and the size of buckets oi'said elevator are so proportioned that when the elevator is operated the screw conveyer 2| will give a controlled feed to the boot of the elevator so that no parts of the elevator will be overloaded.

In Fig. 3 cf the drawing, a modification of the feed control mechanism between the grit hopper 1.6 and the boot of the elevator I1 is shown,

the only significant difierence, as compared with Fig. 2, being that a bafile plate 24 is provided adjacent the discharge end of the feed pipe 20, which, when looking along the axis of the shaft 22, completely covers the opening of feed pipe 20 but which is actually spaced therefrom preferably adjacent its bottom, it being attached IT, as controlled by the screw conveyer 2.1,, feed pipe 20 and the baflle plate. 24.

When the screw conveyer 2i and elevator I! are idle. there will be. substantially no flow of solids through the feed pipe 20 and thus there will be no tendency for the dewatering elevator to become choked up during inactive periods. This makes it entirely practical tov operate the complete installation only intermittently without there being any objectionable overloading of the apparatus, since under normal conditions the solids will not accumulate at such a rate as to justify the continuous operation of the elevator 11, the washer I 9 and the grinder 15.

From the foregoing it will be seen that the baiiie 24 cooperates to form a downwardly extending path for grit fed from the tank through the feed pipe 20 to the elevator and that there includes flights adapted to scrape settled material from the bottom of the basin, settling tank or grit channel Ill and scrape it into the grit hopper 16. Any standard drive mechanism, not illustrated, may be employed to drive the scraper conveyor 25.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claim hereto appended, and applicant therefore wishes not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment, of the invention, what it is desired to secure by Letters Patent of the United States is:

Apparatus for removing grit from sewage including in combination, a grit channel into which settleable solids flow in a fluid stream, a screen at the influent end of said grit channel, for removing trash from said fluid stream beiore it flows into said grit channel, a: grit hopper in the bottom of said grit channel adjacent its infiuent end. extending transversely thereof and downstream of said screen whereby the first grit to settle from said fluid stream collects in said grit hopper, a scraper conveyor in said grit channel downstream of said grit hopper for scraping. grit in an upstream direction into said grit hopper, a bucket elevator at one side of said grit channel having. a foot shaftadjacent one end of said grit hopper, wall means: separating said bucket elevator from; said grit channel, a short cylindrical feed pipe substantially in axial alignment with said bucket elevator foot. shatt connecting said grit hopper and bucket elevator, a screw conveyor in. said grit hopper extending substantially the full length thereof and at its discharge end extending into said short cylindrical feedv pipe, and a baflle in said elevator cooperating to form a downwardly extending path for grit discharged from the end of said; cylindrical feed pipe, said baflle having its botom edge spaced from; said feed: pipe. and the bottom. of said elevator, said. bucket elevator foot shatt being common to both said bucket elevator and said screw conveyor whereby when said bucket elevator is operated said screw conveyor is: operated is always some grit at the bottom of the elevator. will extend below or into this grit at the bottom of the elevator when the elevator 11' and screw conveyer 2| are not operating and therefore when this condition exists grit, in order to forced into the grit at the bottom of the ele- Thus the screw conveyer 2| and tube 20 cooperate when the conveyer 21 starts to The bottom end or edge of the bafiie 24 .pass from the tank to the elevator, must be extrude the grit into the bottom of the ele- I,

vator [1.

It is important to note that in the operation of the apparatus the first solids to settle in the grit channel I0 collect in the grit hopper 16 and that those solids which are the last to settle, that is, those solids which settle from the sewage stream after it has flown over the grit hopper 16, are conveyed in the upstream direction in the grit channel [0 toward the influent end thereof and are discharged into said grit hopper Hi. This conveying of the last solids to settle is effected by a settled solids scraper conveyer 25 which is of essentially standard construction and to feed grit at such a rate that. said bucket elevator cannot become overloaded, said screw con veyor, feed pipe and bafile cooperating to stop the flow of grit from said grit hopper into said elevator when said: elevator is not. in operation.

SAMUEL L. TOLMAN References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,334,841 Cooley Mar. 23, 1920 1,404,573 McGee .Ian. 31, 1922 1,716,228 Horne June 4,v 1929 2,052,091 Green Aug, 25,. 1936 2,131,690 Marshall Sept. 2'1, 1938 2,137,421 Tark Nov, 22, 1938 2,221,444 Dodge et al Nov. 12, 1940 2,254,176. Fischer Aug. 26, 1941 2,267,608 Hawle'y Dec.,23, 1941 2,309,002 Nichols Jan. 19,. 1943 2,425,932 Green et a1. Aug. 1-9", 1947 2,517,117 Komline Aug.1,. 1950 FOREIGN PATENTS Number Country Date 440,428 Germany of 1927 

